Scientists have developed a new mind-reading technology that can predict a person's thoughts by analysing their brainwaves, an advance that may allow speech-impaired people to communicate. The technology can recognise the numbers zero to nine with 90 per cent accuracy using electroencephalogram (EEG) readings while the subject utters the numbers. It can also recognise 18 types of Japanese monosyllables from EEG signals with 60 per cent accuracy, demonstrating the possibility of an EEG-activated typewriter in the near future. The research group from Toyohashi University of Technology in Japan collected EEG data of subjects speaking Japanese digits and monosyllables.
Using this data, the group conducted digit and monosyllable recognition experiments. Up until now, speech decoding via EEG signals has been inhibited by a lack of data to allow the use of powerful algorithms based on deep learning or other types of machine learning. The research group has developed a different research framework that can achieve high performance with a small training dataset. The new framework is based on holistic pattern recognition using category theory, or composite mapping, in which a dual space and a tensor space including exterior algebra are introduced. In the experiment of spoken-digit recognition from EEG signals, 90 per cent recognition accuracy was achieved. At the same time, 61 per cent accuracy in 18 Japanese monosyllable recognition was achieved, outperforming previous research efforts. Humans have sufficient intelligibility of sentences with an 80 per cent monosyllable recognition rate. Researchers aim to develop a brain computer interface that recognises unvoiced speech, or speech imagery. This technology may enable handicapped people who have lost the ability of voice communication to speak once again. It is also expected that the technology would give a healthy person the most natural interface without any limitations. The research group plans to develop a device that can be easily operated with fewer electrodes and connected to smartphones within the next five years.